MB90520 Series
s MEMORY MAP
Single chip mode
A mirroring function
is supported.
FFFFFFH
ROM area
Address #1
FE0000H
010000H
Address #2
ROM area
(image of
bank FF)
004000H
002000H
Address #3
000100H
0000C0H
000000H
RAM Register
Peripheral
Part number
MB90522
MB90523
MB90F523
Address #1*
FF0000H
FE0000H
FE0000H
Address #2 *
004000H
004000H
004000H
: Internal access memory
: Access prohibited
*: Addresses #1, #2 and #3 vary with product type.
Address #3 *
001100H
001100H
001100H
Note: The ROM data of bank FF is reflected in the upper address of bank 00, realizing effective use of the C
compiler small model. The lower 16-bit of bank FF and the lower 16-bit of bank 00 are assigned to the
same address, enabling reference of the table on the ROM without stating “far.”
For example, if an attempt has been made to access 00C000H, the contents of the ROM at FFC000H are
actually accessed. Since the ROM area of the FF bank exceeds 48k bytes, the whole area cannot be
reflected in the image for the 00 bank. The ROM data at FF4000H to FFFFFFH looks, therefore, as if it
were the image for 00400H to 00FFFFH. Thus, it is recommended that the ROM data table be stored in
the area of FF4000H to FFFFFFH.
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